1.4 Chromatography
Assumed knowledge

This subtopic builds upon concepts of polarity introduced in Stage 1 subtopics 3.1 and 3.2. Ion exchange is developed in subtopics 4.2 and 4.3.

Chomatography techniques

Chromatography techniques, including thin layer chromatography (TLC), gas chromatography (GC), high-performance liquid chromatography (HPLC), and ion chromatography (IC), involve the use of a stationary phase and a mobile phase to separate the components of a mixture.

The rate of movement of the components is caused by the differences between the strengths of the interactions between atoms, molecules, or ions in the mobile and stationary phases.

  • Predict the relative rates of movement of components along a stationary phase on the basis of their polarities and charge, given the structural formulae or relative polarities of the two phases.

Videos: Chromatography, Gas Chromatography (or alternative)

Animated notes (use Microsoft Edge)

Rf values and retention times

Data from chromatography techniques can be used to determine the composition and purity of substances.

  • Calculate and apply RF values and retention times in the identification of components in a mixture.

Animated notes (use Microsoft Edge)

TLC Experiment 2018

Ion exchange

Ion chromatography (also known as ion exchange chromatography) is used to remove either cations or anions from a mixture by replacing them with ions of another type.

  • Explain, using equilibrium principles, how ions attached to the surface of a resin can be exchanged with ions in aqueous solution.

Videos: IC in practice, Using IC to collect a protein

Extra questions
Chromatography Questions.pdf
Chromatography Answers.pdf